The purpose of this project, entitled "Pathology Support for the National Toxicology Program (NTP)", is to provide a wide range of pathology support for the NTP contract studies and in-house NIEHS studies. This support will include providing necropsy assistance, tissue processing, and slide preparation for program-related studies conducted in-house as well as for additional studies involving special pathology techniques and evaluations on pathology specimens generated through other contracted studies; reviewing and providing written evaluation of results of toxicity/carcinogenicity studies performed by other contractors; conducting or serving as a member of NTP Pathology Working Group reviews; and technical support including pathology data entry. This support is necessary for the pathology portion of NTP studies where microscopic review or additional gross tissue examination, trimming, and slide preparation must be performed before final evaluation of the study by NTP staff can be completed.